JPH0354165A - Ptc ceramic composition and production thereof - Google Patents

Abstract

PURPOSE:To decrease the specific resistance and increase the dielectric strength of the subject composition composed of barium titanate by using a raw material for chemical process in place of a raw material for solid-phase reaction process and utilizing the characteristic feature of the material. CONSTITUTION:BaTiO3, SrTiO3, PbTiO3 and CaTiO3 are separately synthesized by liquid-phase solution reaction process. The synthesized titanates are used as raw materials for the main component expressed by formula (Ba1-x-y-zSrxPbyCaz)TiO3 (0.05<=x<=0.2, 0.03<=y<=0.2, 0.05<=z<=0.15). The main component is compounded with an atomic valence controlling agent composed of 0.2-0.5mol% of one or more elements selected from Sb, Bi, Nb, Ta and rare- earth elements, 0.02-0.08mol% of Mn and <=0.45mol% of Si and the obtained mixture is calcined. The amount of SiO2 to be added as a calcination assistant can be decreased by this process to obtain a PTC ceramics having low specific resistance and high dielectric strength which cannot be attained by conventional process.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a barium titanate-based PTC (Positi
ve Temperature Cocf'l'i
clent) porcelain composition and its manufacturing method.

[Conventional technology] In general, the characteristics of barium titanate-based PTC ceramics for current limiting elements include a small resistivity at room temperature, a large rate of change in resistance, a large temperature coefficient of resistance, and a high withstand voltage. There are things, etc. Among these, especially
Characteristics required of PTC ceramics for current limiting elements include as low a specific resistance as possible and a high withstand voltage. The reason for this is that when comparing elements with the same rated voltage, if the specific resistance is small, an element with even lower resistance can be obtained, and if the withstand voltage is high, an element with a thinner and smaller size can be obtained. At the same time, it is also possible to use it in higher voltage circuits.

Many proposals have been made regarding compositions and manufacturing methods for barium titanate-based PTC ceramics, but in all cases, the withstand voltage decreases as the specific resistance decreases. On the other hand, if an attempt is made to improve the withstand voltage, there is a disadvantage that the specific resistance increases.

For this reason, conventional low-resistance barium titanate-based PTC ceramics have a specific resistance of 5 Ωcm and a withstand voltage of 20 to 30 v/l.
Il1 specific resistance 10ΩcIm withstand voltage 40-60V/II
This is the ratio of withstand voltage to specific resistance (V8
/ρ2,), all of them are 4 to 6 or less, and the withstand voltage is small compared to the specific resistance, which is not practical.

Conventional barium titanate-based PTC ceramics contain, in addition to the main components BaO and TiO2, SrO and PbQ as Curie point shifters, and Sb as a valence control agent.
20s, Nb20s and rare earth elements, MnO as a resistance temperature coefficient improver, and S as a sintering aid.
The composition contains LOz, AR20, etc. When manufacturing such PTC ceramics, various mixed raw materials are wet-mixed and then calcined at a temperature of about 1000 to 1200°C, and BaTiOx is produced by a so-called solid phase reaction method.
This is crystallized as a powder, and after pulverizing it again, it is molded into a desired shape and fired at a temperature of about 1,300 to 1,400°C.

In particular, as a barium titanate semiconductor ceramic composition with high withstand voltage and excellent inrush current characteristics,
There is one described in No. 28324. The PTC ceramics disclosed in this publication is made of barium titanate.
The withstand voltage is improved by simultaneously replacing a part of Pb and Sr, which are Curie point shifters, and further containing Ca. According to this, the starting materials include BaCO3, P b304 , S r COi , C
a COs and TiO2, and in addition to these, MnCOq and SiO were used as a semiconductor agent and as a sintering agent. are added in a predetermined ratio and wet-mixed, and then crystallized as barium titanate-based porcelain by a so-called solid phase reaction method.

[Issue 8 to be solved by the invention] However, the withstand voltage characteristics of the above-mentioned PTC ceramics are 200 to 250 V/2 for those with small specific resistance.
Although it shows a withstand voltage of about Iam, the specific resistance is at most 4
0 to 50 Ωcm, and the ratio of withstand voltage to specific resistance (Va
/ρ25) is generally in the range of 4 to 6, and it cannot be said that the withstand voltage with respect to specific resistance is outside the conventional range.

Generally, it is known that the withstand voltage of barium titanate-based PTC ceramics can be improved by reducing the crystal grain size of the ceramics as small as possible. Regarding this, in the prior art, the following (1) to (3)
), various improvements have been made.

(1) Adding a component that has a crystal grain growth suppressing effect and a uniformizing effect.

(2) The pulverized particle size after pre-calcination is made uniform and fine.

(3) Keep the main firing temperature as low as possible.

In particular, the above-mentioned prior art is characterized by the fact that it starts from raw materials produced by a solid phase reaction method. That is,
Metal carbonates, metal oxides, etc. are provided as raw materials, mixed in a predetermined ratio, wet mixed, and then crystallized according to a so-called solid phase reaction method to obtain the desired ceramics.

However, in any of the above conventional methods,
Although the crystal grain size is reduced to an average of about 10 Iim, which contributes to improving the withstand voltage, it also increases the specific resistance, so
PTC ceramics with low resistivity and high withstand voltage cannot be obtained.

The present invention has been made in view of the above circumstances, and provides a barium titanate-based PTC porcelain composition that has a low specific resistance at room temperature and a high withstand voltage, and a method for manufacturing the same, and in particular, it provides a method for manufacturing the same. For limiting elements, the average crystal grain size is 10 μm or less, the resistivity is 3 to 10 Ωcm, and the withstand voltage is 40 to 200 V/mm, that is, the ratio of withstand voltage to resistivity (Va/ρ2,) is 10. It is an object of the present invention to provide a barium titanate-based PTC ceramic composition having the above characteristics.

[Means for Solving the Problems] The PTC porcelain composition according to the present invention has the following characteristics:
by Cat ) T l 03
0.2 to 0.5 mol% of one or more elements among Sb, Bi, Nb, Ta, and rare earth elements as a valence control agent to the main component composition consisting of, and
Mn is 0.02-0.08 mol% and Si is 0.45
The main component composition contains BaTiO synthesized by a liquid phase solution reaction method.
3SrTiO,, PbTiO3, and C a T I O *, 0,05≦x≦0.
2, 0.03≦y≦0. 2, 0. 05≦z≦0.
It is characterized by the ingredients being blended in a ratio of 15%.

The method for producing the above PTC porcelain composition includes BaTiO. , SrTiO3, PbTiO, and CaTt03 were synthesized by a liquid phase solution reaction method, and the main components (Bal-x-ff-Sr, Pb, Cat )T
ie. is O. 05≦x≦0. 2, 0. 03≦y≦
0.2, 0.05≦z:iko. 15, one or more elements among Sb, Bi, Nb, Ta, and citrus elements as valence control agents in a proportion of 0.2 to 0.5 mol%, and Mn 0.02-0.08 mol%
and Si in a proportion of 0.45 mol% or less,
This is characterized by being shaped and fired.

Moreover, the PTC porcelain composition according to the present invention is ':E3a+
-t-y-I S rt Pb, Cat ) T i
With respect to the main component composition consisting of ,
Mn is 0.02-0.08 mol% and S1 is 0.45
The main component composition is directly contained in a proportion of 0.05≦x≦0.2,0 by a liquid phase solution reaction method.
．． It is characterized in that the ingredients are blended in a ratio of 03≦y≦0, 2,0.05≦z≦0.15.

The method for producing the above PTC porcelain composition includes Ba-containing material, Sr-containing material,
The main component (Ba, -x
-y- s rx Pb, Cat ) Tie, 0
．． 05≦x≦0.2, 0.03≦y≦0.2, 0.05
It is directly synthesized in a ratio of ≦z≦0.15, and sb, Bi, Nb, Ta,
and one or more rare earth elements in an amount of 0.2 to 0.
5 mol% and Mn is 0.02 to 0.08
It is characterized in that the components are blended at a ratio of 0.45 mol% or less and Si is 0.45 mol% or less, and this is subjected to preform firing.

Furthermore, the PTC porcelain composition according to the present invention has (Bat-*
-y-hm S rx P by Cat Ma)T
ie, or (Ba, -m-, -S r.Pb,C
ax ) (T i l-* Ma) 01, Sb,
One or more elements among Bi, Nb, Ta, and rare earth elements are present in a predetermined proportion, and Mn is 0.02 to 0.08
mol% and Si are contained in a ratio of 0.45 mol% or less, and the main component introduction product is directly 0.05≦x≦0.2, 0.03≦y≦ by a liquid phase solution reaction method. 0.2,0.
It is characterized in that the ingredients are blended in a ratio of 05≦z≦0.1.5, 0.002≦a≦0.005.

The method for producing the above PTC porcelain composition includes Ba-containing material, Sr-containing material,
The Pb-containing material, the Ca-containing material, and one or more elements selected from among Sb, Bi, Nb, Ta, and rare earth elements as the valence control agent M are mixed into a solution, and from this the main component is mixed by a liquid-phase branching reaction method. (Ba+−x−y−+− S r
x Pb, Can Ma) Tie, or ( B a
l-x-y-+ S r w P b , C a r
) (T t l-m Ma) 0 3, 0.0
5≦x≦0.2, 0.03≦y≦0.2, 0.05≦z
50.15. Directly synthesized at a ratio of 0.002≦a≦0.005, and with respect to this main component composition, Mn is added from 0.02 to
It is characterized in that 0.08 mol % and Si are blended in a ratio of 0.45 mol % or less, and this is molded and fired.

In this case, it is preferable to use either the oxalate method or the hydrothermal synthesis method as the liquid-citrus solution reaction method in each of the above-mentioned production methods.

Note that rare earth elements used as valence control agents include La
, Y, etc.

[Function] The PTC porcelain composition of the present invention is characterized in that a so-called chemical method raw material is used as a starting material. Chemical method raw materials are BaTi obtained by liquid phase solution reaction methods such as oxalate method, hydroxide method, hydrothermal method, alkoxide method, etc.
Crystals such as Oy, sr"rio3, PbTiO, CaTiO, etc., or solid solutions or mixed crystals thereof, which have the following properties (4) to (6) compared to raw materials (crystalline powder) obtained by conventional solid phase reaction methods. ).

(4) Particle size is uniform and fine, and powder activity is high.

(5) High purity.

(6) High compositional uniformity at the molecular level.

The inventors focused on the various characteristics of such chemical raw materials,
Various studies have been conducted on using this material as a starting material for the main component composition of barium titanate-based PTC ceramics. As a result, it was found that the amount of Sin2 added as a sintering aid for barium titanate-based PTC ceramics can be reduced compared to when raw materials obtained by conventional solid phase reaction methods are used.

In the PTC porcelain composition and the manufacturing method thereof according to the present invention, a so-called chemical method raw material is used as a starting material instead of the conventional solid phase reaction method, and a composition has been found that takes advantage of the characteristics of the chemical method raw material. As a result, compared to conventional barium titanate-based PTC ceramics, the specific resistance at room temperature is particularly low and the withstand voltage is high.

As mentioned above, chemical raw materials generally have high purity, uniform particle size, and high powder activity, so if raw materials produced by conventional solid phase reaction methods are used as starting materials , using Sin2 as a liquid phase sintering aid 0.5~2
Add about mol%.

On the other hand, in the porcelain composition of the present invention, Sin
It does not contain 2 at all or its content can be kept low to 0.45 mol% or less, and the sintering temperature is also about 5 mol%.
It has been found that the temperature can be lowered by 0°C. In particular, by providing a chemical method raw material as a starting material, sintering can be performed even when Si02 as a liquid phase sintering aid is not added. This is completely unexpected using conventional techniques that use raw materials produced by the i1 phase reaction method as starting materials, and even more unexpected is that the resistance ratio can be lowered when the crystal grain size is 10 μm or less.

Therefore, the crystal grain size of the ceramic becomes fine, 10 μm or less, and the withstand voltage becomes high. In addition, Si02 usually forms a grain boundary precipitated phase as a glass phase in ceramics, and this phase has low electrical conductivity, and as the amount of S102 added increases, the thermal specific resistance as a ceramic element decreases. tends to become larger.

Next, the reasons for limiting each additive element in the above PTC porcelain composition will be explained.

When X is less than 0.05, Sr has insufficient electrical properties and its mechanical and thermal strength tends to decrease.On the other hand, when X exceeds 0.2, the Curie point is 80°C or lower. Therefore, it is not practical as a current limiting element.

For Pb, if y is less than 0.03, the effect of improving characteristics regarding high withstand voltage ratio will be small, while if y exceeds 0.2, the Curie point will exceed 150°C, making it difficult to use as a current limiting element. At the same time, the specific resistance at room temperature tends to increase.

When 2 is 0.05 or less, Ca has no effect on uniform miniaturization, that is, high withstand voltage; on the other hand, when 2 is 0.05 or less,
When it exceeds 15, the specific resistance becomes large.

The valence control agent may be added in an amount less than 0.2 mol% or more than 0.5 mol%, i.e. from 0.2 to 0.5 mol%.
When the mol% is out of the range, the resistance tends to increase.

If the amount of Mn added is less than 0.02 mol%, the temperature coefficient of resistance in the PTC region will be 8%/℃ or less, making it unusable. On the other hand, if it exceeds 0.08 mol%, the specific resistance at room temperature will sharply decrease. increases.

When the amount of 5i02 added exceeds 0.45 mol%,
The room temperature specific resistance becomes large, which does not meet the purpose of the present invention and is not practical.

[Embodiments] Various embodiments of the present invention will be described below with reference to the accompanying drawings.

Example 1 FIG. 1 is a process diagram showing a method for manufacturing a PTC ceramic composition according to a first example of the present invention. Table 1 is a table showing ceramic compositions of Examples of the present invention and Comparative Examples.

BaTiO, , SrTiO, , PbTiO, CaTiO
, respectively, by a liquid phase solution reaction method, each raw material powder is prepared (Step 10).

Among these, BaTiO,, SrTiO3, C a T
BaCO3, S rco3CaC for i O J
Synthesized by oxalate method using O3, Ti02 as raw materials, P
b T i O 3 is synthesized by a hydrothermal synthesis method using PboTie2 as a raw material. Hereinafter, in order to simplify the explanation, only the synthesis of BaTi03 will be explained.

Baco and Tie2 powders are added to the respective predetermined solutions and thoroughly stirred and mixed (Step 11).

Adding the specified alkaline solution to the mixed solution (Wang Cheng 12)
.

BaTiOs is precipitated by the reaction between BaCO3, T i02 and each solution (step 13).

The precipitate is heated to a predetermined temperature and dried (step 14).

Grind and weigh the dry material. At this time, the first proportion is
No. in the table. 5 to 33, BaTiO. ,S
rTiO3, PbTt03, and CaTiO are each weighed (step 15).

48 titanates were mixed in a solid state, and further La, Y
Appropriate amounts of rare earth elements such as Sb, Bi, Nb, and Ta are added as valence control agents, MnCO3 as a resistance d coefficient improver, and Si02 as a sintering aid. 16).

The removed product is pulverized and mixed in a ball mill for about 10 hours, and then dehydrated and dried. Approximately 3 cc of 6% PVA was added to 100 grams of sample, and the molding pressure was 1000 kg/
It is shaped into a pellet with a diameter of 15 square meters and a thickness of 1.5 square meters (step 17).

The pellet is calcined at a predetermined temperature (step 18).

After calcining, the pellets are crushed (one step).

A binder is added to the pulverized material and shaped into a desired shape (step 20).

The molded product is fired. The conditions for the main firing are a temperature increase rate of 200°C per hour, a firing temperature of 1280 to 1340°C,
After being incinerated for about 1 hour, it was allowed to cool naturally in the furnace (Step 21
). A device was prepared by baking an Ag electrode with good ohmic contact onto the PTC ceramic thus obtained, and its Curie point, specific resistance at room temperature, and withstand voltage were measured.

Example 2 FIG. 2 is a process diagram showing a method for manufacturing a PTC ceramic composition according to a second example of the present invention.

BaCO3, SrC03, PbO, CaCO3 and T
ie2 is adjusted respectively (step 30).

That is, the component composition is No. 1 in Table 1. Each raw material powder is weighed so as to have a weight of 5 to 33.

Each weighed raw material powder is added to a predetermined solution and thoroughly stirred and mixed (Wang Cheng 31).

Adding a predetermined alkaline solution to the mixed solution (Step 32)
.

Due to the reaction between each raw material powder and each solution (B a 1-*-y-, Srt Pb, Cal
) Tie3 coprecipitates (Wang Cheng 33).

The precipitate is heated to a predetermined temperature and dried (step 34).

Grind and weigh the dry material. (Step 35).

(Bat-m-y-g S rt P by Cat
) In addition, rare earth elements such as La and Y or Sb, Bi, Nb, and Ta are used as valence control agents, Mn CO3 is used as a resistance temperature coefficient improver, and Si is added to the powder of TtO.
Appropriate amounts of n2 are added as sintering aids (step 36).

The mixture is pulverized and mixed in a ball mill for about 10 hours, and then dehydrated and dried. Approximately 3 cc of 6% PVA was added to 100 grams of sample, and the molding pressure was 1000 kg/
Molded with aII13, diameter 15I and thickness 1.5mII
(Step 37).

The pellet is calcined at a predetermined temperature (step 38).

After calcining, the pellets are crushed (step 39).

A binder is added to the pulverized material and molded into a desired shape (step 40).

The molded product is fired. The conditions for the main firing were a heating rate of 200'C/hour, a firing temperature of 1280-1340°C, and after firing for about 1 hour, it was allowed to cool naturally in the furnace (Step 4).
1). A device was prepared by baking an Ag electrode with good ohmic contact onto the PTC ceramic thus obtained, and its Curie point, specific resistance at room temperature, and withstand voltage were each determined to be 4Pj.

Example 3 FIG. 3 is a process diagram showing a method for manufacturing a PTC ceramic composition according to a third example of the present invention.

BaCO3, SrCO,, PbO, CaCO3? and T
ie2 is adjusted respectively (step 50).

That is, a certain proportion is No. 1 in Table 1. Weigh each raw material powder so that the weight is 5 to 33.

Add an appropriate amount of valence control agent M to each weighed raw material powder, dissolve it in a predetermined solution, and stir and mix thoroughly (Step 5)
1).

Adding a predetermined alkaline solution to the mixed solution (step 52)
.

Due to the reaction between each raw material powder and each solution (B a l--y-+ - S r- P by
Cat Ma) Tie, or (B a l-
x-y-rSrxPbyCa+)(Ti
, - Ma) O. is coprecipitated (step 53).

The precipitate is heated to a predetermined temperature and dried (step 54).

Grind and weigh the dry material. (Step 55).

(Bit-m-,-+■ S r* Pb, Cat
Ma) Tie, or (B a r-x-1-+ S
rtPbyCa,)(Ti1-Ma)0
Further, appropriate amounts of M n CO 2 as a resistance temperature coefficient improver and SiO 2 as a sintering aid are added to the powder of No. 3 and mixed (step 56).

The mixture is pulverized and mixed in a ball mill for about 10 hours, and then dehydrated and dried. Approximately 3 cc of 6% PVA was added to 100 grams of sample, and this was heated at a pressure of 1000 kg/
cta" to form pellets with a diameter of 15 nv and a thickness of 1.5 cm (step 57).

The pellets are calcined at a predetermined temperature (step 58).

After calcining, the pellets are crushed (step 59).

A binder is added to the pulverized material and it is shaped into a desired shape (step 60).

The final firing of the cylindrical object is carried out. The conditions for the main firing are a heating rate of 200°C per hour, a firing temperature of 1280 to 1340°C,
After baking for about 1 hour, it was allowed to cool naturally in the furnace (Step 61).
). A device was prepared by baking an Ag electrode with good ohmic contact onto the PTC ceramic thus obtained, and its Curie point, specific resistance at room temperature, and withstand voltage were measured.

Comparative example (adjustment using solid phase reaction raw materials) BaCO
3, SrCO3, PbO, CaCO3, Ti02,
Powders of Sb2 03 , MnCO3 , MnCOi , and Sin2 were each weighed, ground and mixed in a ball mill for 10 hours, and then dehydrated and dried.

After adding 6% PVA to this and performing primary molding, it was heated to 1050°C.
Calcinate at a temperature of 2 hours. After calcination, 1
After pulverizing for 0 hours and dehydrating and drying, 6% PVA was added to sample 1.
Approximately 3cc is added to 00 grams, and the molding pressure is 10
Molded at 00kg/cm2, diameter 15} and thickness 1.5
It is assumed to be a mm beret.

The conditions for the main firing were a heating rate of 200"C per hour and a firing temperature of 1300°C. After firing for about 1 hour, it was allowed to cool naturally in the furnace.The PTC ceramics thus obtained were Elements were prepared by baking Ag electrodes with good contact, and their Curie point, specific resistance at room temperature, and withstand voltage were measured.

As is clear from Table 1, the ratio of i1 voltage to room temperature resistivity (V8/ρ2,) of the PTC ceramics of each example is significantly increased compared to that of the comparative example, and most of the PTC ceramics are 1
It comes to show a VB/ρ2 value of 0 or more. On the other hand, in the comparative example, even if the composition is within the range of the fractional composition of the present invention, such as NO, 1, the room temperature specific resistance p2 is about 100Q.
It is as large as cm. Also, like Comparative Examples No. 2 to 4,
As SiO2 is further added, the room temperature specific resistance ρ2-i decreases to 40 Ωcm at an addition amount of 1 mol%, but increases to 80 Ωcm at an addition amount of 2 mol%. In other words, the PTC ceramics produced by the conventional method have a specific resistance at room temperature of ρ2, 3 to 10Ωco, and a withstand voltage of 40 to 200Ω.
It was found that it did not clear V/mm.

[Effects of the Invention] According to the present invention, a PTC with low resistivity and high withstand voltage, which has been difficult to achieve with conventional compositions and manufacturing methods, can be produced.
You can get Cerami Sox.

As a result, it is possible to manufacture elements with lower resistance for the same rated voltage, making it possible to put into practical use current limiting elements for even larger loads, as well as to put into practical use thinner and smaller resistive elements than before. can be converted into

[Brief explanation of drawings]

FIG. 1 to FIG. 3 each show P according to an embodiment of the present invention.
FIG. 2 is a process diagram showing a method for producing a TC ceramic composition.

Claims (1)

[Claims] (1) (Ba_1_-_x_-_y_-_zSr_xP
b_yCa_z) For the main component composition consisting of TiO_3, 0.2 to 0.5 of one or more elements among Sb, Bi, Nb, Ta, and rare earth elements are added as a valence control agent.
Mn is contained in a proportion of 0.02 to 0.08 mol% and Si is contained in a proportion of 0.45 mol% or less, and each of the main component compositions is prepared by a liquid phase solution reaction method. Synthesized BaTiO_3, SrTiO_3, PbTiO
_3, and CaTiO_3, 0.05≦x≦
0.2, 0.03≦y≦0.2, 0.05≦z≦0.1
PTC characterized by having ingredients blended in a ratio of 5.
Porcelain composition. (2) BaTiO_3, SrTiO_3, PbTiO_
3, and CaTiO_3 were each synthesized by a liquid phase solution reaction method, and using these four types of titanates, the main component (Ba_1_-_x_-_y_-_zSr_xPb_y
Ca_z) TiO_3 is 0.05≦x≦0.2, 0.0
Sb, Bi, Nb, Ta,
and one or more rare earth elements in an amount of 0.2 to 0.
A PTC porcelain composition characterized in that the components are blended in a proportion of 5 mol%, Mn in a proportion of 0.02 to 0.08 mol%, and Si in a proportion of 0.45 mol% or less, and then fired. Production method. (3) (Ba_1_-_x_-_y_-_zSr_xP
b_yCa_z) For the main component composition consisting of TiO_3, 0.2 to 0.5 of one or more elements among Sb, Bi, Nb, Ta, and rare earth elements are added as valence suppressants.
Mn is contained in a proportion of 0.02 to 0.08 mol% and Si is contained in a proportion of 0.45 mol% or less, and the main component composition is directly reacted by a liquid phase solution reaction method. 0.0
5≦x≦0.2, 0.03≦y≦0.2, 0.05≦z
A PTC porcelain composition characterized in that components are blended in a ratio of ≦0.15. (4) Ba-containing materials, Sr-containing materials, Pb-containing materials, and C
The a-containing material is mixed into a solution, and the main component (Ba_1_-_x_-_y_-_zSr_
xPb_yCa_z)TiO_3, 0.05≦x≦0
．． 2, 0.03≦y≦0.2, 0.05≦z≦0.15
directly synthesized at a ratio of 0.2 to 0.5 mol% of one or more elements among Sb, Bi, Nb, Ta, and rare earth elements as a valence control agent to this main component composition. and 0.02 to 0.08 mol% of Mn and Si
A method for producing a PTC porcelain composition, which comprises blending the ingredients in a proportion of 0.45 mol% or less and firing the mixture. (5) (Ba_1_-_x_-_y_-_z_-_nS
r_xPb_yCa_zMa)TiO_3 or (Ba
_1_-_x_-_y_-_zSr_xPb_yCa_
z) Sb, Bi, Nb as the valence suppressant M for the main component composition consisting of (Ti_1_-_aMa)O_3
, Ta, and one or more elements among rare earth elements in a predetermined proportion, and Mn in a proportion of 0.02 to 0.08 mol% and Si in a proportion of 0.45 mol% or less, The main component composition is directly 0.0% by liquid phase solution reaction method.
5≦x≦0.2, 0.03≦y≦0.2, 0.05≦z
A PTC porcelain composition characterized in that the components are blended in a ratio of ≦0.15, 0.002≦a≦0.005. (6) Ba-containing materials, Sr-containing materials, Pb-containing materials, Ca-containing materials, and Sb, Bi, Nb, and T as valence control agents M.
a, and one or more rare earth elements are mixed into a solution, and then the main component (Ba_
1_-x_-y_-z_-_nSr_xPb_yCa_
zMa) TiO_3 or (Ba_1_-_x_-_y
____zSr_xPb_yCa_z)(Ti_1_-_
aMa) O_3, 0.05≦x≦0.2, 0.03≦
It is directly synthesized in the ratio of y≦0.2, 0.05≦z≦0.15, 0.002≦a≦0.005, and Mn is 0.02 to 0.08 to this main component composition. 1. A method for producing a PTC porcelain composition, which comprises blending components in a proportion of 0.45 mol% or less and Si at a ratio of 0.45 mol% or less, and firing the composition. (7) Claims 2 and 4, characterized in that the liquid phase solution reaction method uses either an oxalate method or a hydrothermal synthesis method.
6. A method for producing a PTC porcelain composition as described in 6.